Final answer:
The roll trim tool in aviation should be used when an aircraft tends to roll to one side or when continuous input is needed to maintain level flight. This can occur after changes in weight distribution, fuel consumption, or when flying in crosswind conditions.
Step-by-step explanation:
The roll trim tool is an essential component in aviation, specifically used to adjust the aircraft's roll characteristics to achieve a balanced and stable flight. Pilots usually engage the roll trim to alleviate any constant pressure they might need to apply to the control yoke or stick to keep the aircraft wings level. The tool is particularly useful during various phases of flight including after changes in weight distribution, fuel consumption, or when flying in turbulent or crosswind conditions. It helps in counteracting any rolling moments caused by imbalanced loading or aerodynamic forces.
The main answer to the question of when to use the roll trim tool is: a pilot should use it whenever they notice the aircraft has a tendency to roll to one side or when continuous control input is required to maintain level flight. An example would be after a change in the center of gravity due to passengers moving within the cabin, or after fuel has been burned from one wing tank more than the other. Consequently, utilizing the roll trim tool ensures that the aircraft flies straight with minimal pilot workload and contributes to safer flight operations.